Title: | Glc7p protein phosphatase inhibits expression of glutamine-fructose-6-phosphate transaminase from GFA1 |
Author(s): | Zheng J; Khalil M; Cannon JF; |
Address: | "Department of Molecular Microbiology and Immunology, University of Missouri, Columbia, Missouri 65212, USA" |
ISSN/ISBN: | 0021-9258 (Print) 0021-9258 (Linking) |
Abstract: | "Inhibitor-1 (I-1) is a specific inhibitor of protein phosphatase-1 (PP1). We assayed the ability of I-1 to inhibit Saccharomyces cerevisiae PP1, Glc7p, in vivo. Glc7p like other PP1 catalytic subunits associates with a variety of noncatalytic subunits, and Glc7p holoenzymes perform distinct physiological roles. Our results show that I-1 inhibits Glc7p holoenzymes that regulate transcription and mitosis, but holoenzymes responsible for meiosis and glycogen metabolism were unaffected. Additionally, we exploited a genetic screen for mutants that were dependent on I-1 to grow. This scheme can identify processes that are negatively regulated by Glc7p-catalyzed dephosphorylation. In this paper I-1-dependent gfa1 mutations were analyzed in detail. GFA1 encodes glutamine-fructose-6-phosphate transaminase. One or more phosphorylated proteins activate GFA1 transcription because the pheromone response and Pkc1p/mitogen-activated protein kinase pathways positively regulate GFA1 transcription. Our findings show that an I-1-sensitive Glc7p holoenzyme reduces GFA1 transcription. Therefore, GFA1 is a member of a growing list of genes that are negatively regulated by Glc7p dephosphorylation" |
Keywords: | "Catalysis Fungal Proteins/genetics/*metabolism Glutamine-Fructose-6-Phosphate Transaminase (Isomerizing)/genetics/*metabolism Mutagenesis, Site-Directed Phosphoprotein Phosphatases/*metabolism Phosphorylation Plasmids Protein Phosphatase 1 Saccharomyces c;" |
Notes: | "MedlineZheng, J Khalil, M Cannon, J F eng AI07276/AI/NIAID NIH HHS/ GM40326/GM/NIGMS NIH HHS/ Research Support, Non-U.S. Gov't Research Support, U.S. Gov't, P.H.S. 2000/04/15 J Biol Chem. 2000 Jun 16; 275(24):18070-8. doi: 10.1074/jbc.M000918200" |